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研究滨海湿地围垦养殖后沉积物有机碳库的动态变化,对科学评估沿海滩涂湿地开发利用对碳库的影响具有重要意义.以闽江口鳝鱼滩湿地为研究区,采集不同围垦年限(3 a和15 a)养殖塘和短叶茳芏(Cyperus malaccensis)(养殖塘围垦前主要土著植被)湿地沉积物,测定其总有机碳(TOC)、有机碳组分(微生物生物量碳(MBC)、易氧化有机碳(EOC)、水溶性有机碳(WSOC))及有机碳矿化特征,并基于时空互代法,分析了围垦养殖对沉积物TOC、有机碳组分及矿化的影响.结果表明:围垦养殖3 a,沉积物TOC和WSOC含量总体上没有显著变化,但围垦15a,表层(0~10 cm)沉积物TOC和WSOC含量显著增加,其增加比例分别约为68.36%和68.01%;围垦养殖后,沉积物MBC没有显著变化,EOC含量则有所降低,围垦15 a后表层沉积物EOC含量约降低37.35%.围垦养殖后表层沉积物有机碳矿化速率和累积矿化量均高于短叶茳芏湿地,而亚表层(10~20 cm)沉积物矿化速率差异不显著,且表层累积矿化量高于亚表层.养殖塘沉积物TOC及有机碳组分受长期水淹和饵料添加等管理方式的影响,同时受黏粒、TN和TP等理化性质的间接影响,进一步影响沉积物矿化速率、累积矿化量和潜在矿化量(C0).上述结果预示着滨海湿地围垦养殖在一定程度上增加了沉积物有机碳的蓄积,同时也促进了有机碳矿化.
It is of great significance to study the dynamic changes of organic carbon pools in the coastal wetland after reclamation and aquaculture so as to scientifically assess the impacts of coastal wetland development and utilization on carbon stocks.United with the study on the eel wetland in Minjiang Estuary, a and 15 a) Wetland sediments from the ponds and Cyperus malaccensis (main indigenous vegetation prior to the cultivation ponds reclamation) were measured for total organic carbon (TOC), organic carbon fractions (MBC) EOC, WSOC and organic carbon mineralization were analyzed. The effects of reclamation and aquaculture on TOC, organic carbon composition and mineralization of the sediments were analyzed based on the time-space iterative method. The results showed that the TOC and WSOC contents of the sediments did not change significantly after the reclamation for 3 years, but the contents of TOC and WSOC in the sediments (0 ~ 10 cm) increased significantly after the reclamation for 15 years, with the increasing proportion being 68.36% and 68.01 %. After reclamation and cultivation, MBC of sediment did not change significantly and EOC content decreased, and the EOC content of surface sediment reduced about 37.35% after 15 years of reclamation.The organic carbon mineralization rate and cumulative mineralization of surface sediment after reclamation Are higher than the short-leaved wetlands, while the sub-surface (10 ~ 20 cm), the mineralization rate of sediments was not significant, and the cumulative mineralization of surface layer was higher than that of sub-surface layer.The TOC and organic carbon components in the ponds were affected by long-term flooding and dietary addition, Affected by the physical and chemical properties such as clay, TN and TP, the mineralization rate, cumulative mineralization and potential mineralization (C0) of sediments are further affected.These results indicate that the seashore wetland reclamation increased the sedimentation to a certain extent The accumulation of organic carbon also promotes the mineralization of organic carbon.